Water skiing by towline drawn from a power boat is a popular sports activity, and diverse modes of skiing are practiced for enjoyment, skill, and exhibition, as is well known. While the common ski activity is on water, as lakes, ponds, etc., such enjoyable and challenging activity may also be undertaken over snow-covered fields or long grassy slopes, and the like.
Increasing interest has developed in the use of towable devices drawn behind the towline for the skier's enjoyment other than the many forms of conventional water skis, boards and the like, as for example inflatable devices such as large annular air tubes, similar to but more rugged than so-called inner tubes used for mere flotation play. These inflatable devices are usually attached to the towline in some manner so as to be drawn thereby, and the skier may seek to "ski" with the tube, or oscillate the tube back and forth, or perform other fun or artistic maneuvers. Such devices are commercially available under trade names as "Hi-Planer Water Ski Tube", "Casad Tube", "Water Bug", "Bump-R-Ride", and others.
Quite generally a towline is fixedly attached to the inflatable device with a separate towline and handle for the skier, with both under tension as the device is drawn through the water or over other surfaces. The towline is necessarily attached to the inflatable device as the same is not of streamline or planiform configuration, and offers considerable resistance to being drawn as compared to skis, knee boards, aqua boards or like sleek devices that are intended for ready planing and speed, as the somewhat ungainly and flexible inflatable device is difficult to accelerate to planing speed, but tends to plow in the water, for example, in the absence of skill and tow power.
As such, if the tow rope is held by the skier and not also connected to the inflatable device, the skier or rider is literally pulled over the front of the tube which is quickly left behind.
Once accelerated to sufficient planing speed, however, the relatively large and somewhat flexible platform afforded by the inner tube is easily gripped by the feed or engaged by other portions of the body, and an amazingly smooth ride is attained at high speed in calm water. This contrast with rigid skis or boards which at higher speeds, by virtue of their rigidity, tend to react quickly to water pressures and bounce harshly, and thus do not serve as stable platforms for activities.
The fixed connection, however, limits the versatility of the inflatable device in that the towline connection obviously precludes foot-controlled spinning of the high speed inner tube, or release of the inner tube so that the rider can undertake barefoot skiing or like skills at higher speeds.